1. Field of Invention
This invention relates to particulate compositions which readily form hair conditioning emulsions, when stirred into heated, acidified water.
2. Description of the Related Art
Modern hair cleansing agents, especially shampoos, while efficiently removing soil from the hair and scalp, simultaneously remove natural protective oils. Repeated use of shampoos (e.g. on a daily basis, not an uncommon practice in our society) may not allow sufficient time for the body to replenish these protective natural oils. As a result, the hair becomes dry, brittle, loses its natural sheen, builds up static electric charges and is difficult to coif.
In order to overcome the deleterious effects of repeated hair washings and permit hair to be clean, yet at the same time attractive, the art has developed a spectrum of post-washing hair conditioning preparations.
Post-washing hair conditioning products well known to the art include cream rinses, spray conditioners, and setting lotions. It is also well known to the art that quaternary ammonium compounds are effective ingredients in such hair conditioning preparations. They are believed to be effective because they possess a positive electrostatic charge, which is attracted to and neutralizes the negative charges of hair protein. The mutual attraction of opposite electrostatic charges thus causes the quaternary ammonium compound to tend to remain on the hair. This tendency to remain on the hair is termed substantivity. Substantive quaternary ammonium compounds not only neutralize the electrostatic charges of hair, but also may provide lubricity, by virtue of their long chain, (i.e. fatty) substituents.
Phenomena associated with quternary ammonium compounds in hair conditioning preparations are discussed for example in an article by T. G. Schoenberg "Role of Alkyl Amino Amine Salts in the Modern Hair Conditioner", Cosmetics and Toiletries, Volume 94, pages 57 et al (1979), which also includes detailed instructions for the preparation of hair care formulations. Hair care formulations prepared with lanolin fatty acid quaternary ammonium compounds are described in "Effects of the Use of Lanolin Acid Quaternary in Human Hair Conditioning Preparations" by J. R. McCarthy and J. M. Laryea, Cosmetics and Toiletries, Volume 94, pages 90 et al, (1979). U.S. Pat. No. 4,526,781 teaches the use of betaines in hair care formulations. Betaines are quaternary ammonium compounds characterized by a zwitterionic structure and exemplified by the reaction product of sodium chloracetate with a fatty dimethyl tertiary amine. The use of quaternary ammonium compounds derived from halo-esters of fatty alcohols as hair conditioners is taught by U.S. Pat. No. 4,370,272. The preparation of a mixture of quaternary ammonium compounds suitable for use in rinsing compositions for human hair is described in U.S. Pat. No. 3,803,137. U.S. Pat. No. 3,211,646 teaches the antistatic properties of mixtures of fatty acid dimethylaminopropyl amides with quaternary ammonium compounds derived from said dimethylaminopropyl amides.
Quaternary ammonium compounds are marketed to formulators as solutions, dispersions, and aqueous pastes. These materialsrequire bulky storage and handling facilities. They are more costly to ship than the solvent-free quaternary ammonium compound, and present formulation difficulties. Solutions and dispersions tend to lose solvent, thus changing the concentration of quaternary ammonium compound dispensed. Sufficient loss of solvent or water may result in precipitation of the quaternary compound itself, leading to unequal distribution. Pastes are physically difficult to dispense and suffer from the same loss of solvent problems as solutions and dispersions. In addition, pastes and dispersions tend to be difficult to emulsify. Quaternary ammonium compounds may be obtained as solids by evaporatively removing the solvents; however, in their solid form, quaternary ammonium compounds are even more difficult to disperse and emulsify than pastes or dispersions. The use of solid quaternary ammonium compounds may introduce variables into the formulation of hair care products because of the presence of variable quantities of residual water or solvents.
In addition to quaternary ammonium compounds, post-washing hair care formulations known in the art may include fatty alcohols and fatty alkylamido alkyldimethylamines, among others. Preparation, physical characteristics and application in cosmetic chemistry of fatty amidoamine derivatives are described in an article by Muzyczko, et. al. (T. N. Muzyczko et. al. "Fatty Amidoamine Derivatives: N,N,-Dimethyl-N-(3 alkylamidopropyl) amines and their Salts." J.O.A.C.S., 45 Pg. 720-5 (1968). They may be prepared by reacting fatty acids with dialkyl amines. The fatty acids may be derived from naturally occuring fats and oils, and thus would have a chain length distribution from about C.sub.8 to about C.sub.22. Synthetic fatty acids may also be used. The combination of fatty alkylamido dimethylamines and a fatty dialkylbenzylamonium chloride for use as a fabric softener is described in German Patent number 2,224,508. A liquid detergent concentrate system packaged for single use application as an industrial cleanser, including fatty alcohols and quaternary ammonium compounds, is taught by U.S. Pat. No. 4,348,292. Thus, the prepackaged liquid concentrate is admixed with the proper quantity of water to obtain a cleansing solution for hard surfaces, bathrooms, and floors. The liquid concentrate taught by said patent consists of two immiscible layers within the same container.